Hi, I'm working again on a stepper motor with a Half-brdige driver to control it with Arduino.

Now, I need to transcode in the PD language this sequence :

1 - 0 1
2 - 1 1
3 - 1 0
4 - 0 0

This is the basic sequence for a stepper motor, did someome know how can i transcode it ??

best and thanks

KinoLAb

Hi, thanks for your answer, but i need to pilot two stepper motor from PD trough Arduino, i'm writing an application that need to be possible to make change live and in real time...

best

En

Hi, this is the driver that i connect to arduino : http://ruggedcircuits.com/html/rugged_motor_driver.html

in arduino I've a patch that read the PWM of two pin and i need to write a sequence like this with the digitals output :

void StepperHighSpeed::stepMotor(int thisStep)
{
if (this->pin_count == 2) {
switch (thisStep) {
case 0: /* 01 */
digitalWrite(motor_pin_1, LOW);
digitalWrite(motor_pin_2, HIGH);
break;
case 1: /* 11 */
digitalWrite(motor_pin_1, HIGH);
digitalWrite(motor_pin_2, HIGH);
break;
case 2: /* 10 */
digitalWrite(motor_pin_1, HIGH);
digitalWrite(motor_pin_2, LOW);
break;
case 3: /* 00 */
digitalWrite(motor_pin_1, LOW);
digitalWrite(motor_pin_2, LOW);
break;
}

did someone can help me ?

Thanks

Best

Enrico

So you want to send the "Steps" to arduino from PD? Why is it that you need this kind of precision? I only ask because stepper motor drivers usually respond to position (in degrees) information, either absolute or relativ; their strength relies on repeatable positioning. I'm not saying you are wrong to do it this way, just may need more info to help you. Mainly, I'm wondering why you are not using one of the impressively robust classes linked to on the ruggedcircuits site.

The easiest way to get data to the arduino from Pd is via serial(which is what the riggedcircuits example does). On the arduino side, you'll need to use the Serial object. Adapting the built-in examples is a great place to start. You'll basically be looking to read in a single Byte, then pass its value (in decimal, or int) to the stepMotor function. On the Pd side, you'll need to look into [comport] which should be easy to figure out / set up for this purpose. Then, I imagine you'll set up a counter, and pipe 0...1...2...3...0 into [comport].

One hitch I see in using only the function below: the motor movement may be "jerky" as the core aligns to each energized magnet. For smooth operation, steppers should be driven by a sinusoidal current, or at the very least - half-stepping. Hopefully the driver board takes care of this interpolation for you?

EDIT: Sorry, looking at your function above, you are half-stepping.

Hi, thanks for your answer, but I think that this solution is to complicate for my knowledge in PD and ARDUINO...

I try to explain you in details the project : I'va a 16mm projector and a 16mm bolex, each one is moved with a stepper motor, so i can be really precise on a 360º movement.
So the idea is to have a patch that allow me to chose 1 movement on the camera then 1 on the projector, or 2 cam and 3 projector etc... and also change the speed of the 360º...

LINK : www.filmelcuento.co.cc/Example.zip

In this link I've poste a n Exemple of patch that I'm trying to use, when you open the patch you have to double click on : "pd sending digital outs" and you have a new window.

In this windows the idea is to recreate the loop that I've send you in the post above.
The TWO specification that i need and that you see on the rugged specification are that with their drive you have :

2 - pins that you have to use with PWM
2 - pins to use with the direction

So i don't know, i remember that with a single H-Bridge and this patch i was able to drive a motor, know the idea is to use the rugged driver....

I hope to be more clear...

Thanks...

Did you look into firmata? In case you don't need to have your own code running on the Arduino, it's a simple firmware that lets you read and write pin values directly from Pd.

BTW, me and my dad had made a video->35mm transfer machine with a stepper motor, but that was back in 1997, before Arduino

No, i don't know how to work in other way that the standard firmata and the pduino...

sorry, but i think that it's possible to found a way to organize the same cycle on PD...
but I'm new in pd so....

best

En

Another BTW - after seeing your website, I gotta tell you I've recently attended a presentation by Pip Chodorov, another die-hard 16mm film fan

good... yes he is a friend of mine...

best

En

OK, get some examples of pduino - it's absolutely the easiest way - you have to upload standard firmata onto Arduino only once, and then, everything you do is from Pd. Much easier than writing your own firmware and communicating through serial port.

It seems the example you posted is meant to be used with firmata. From the readme --

To use it, first download and install Arduino 0018 or newer from
http://arduino.cc. When you run the Arduino program, then you'll be able to
choose firmware from Arduino application, in the menu:

File -> Open -> Examples -> Library-Firmata

yes, I'm using the firmata for PDUINO...

Fascinating project. What aspects of the equipment are you controlling?

Firmata is a good place to start, but I've noticed some lag, I haven't used it in years though.

I would argue that if you are not writing your own firmware, Arduino is overkill for this application. If what you need is Pd to sequence the movement of two steppers, than there are a host of existing options which do not require an Arduino. Googling "USB Stepper Controller" gives you several options, some even targeted at novice/hobbyist uses.

If you do decide to use Arduino, the experience of figuring out the language enough to do what you need will certainly benifit you in the future. ESPECIALLY if digital control of analog equipment is the kind of thing you are in to!

Thanks, I hope to be able to write this cycle.... is really important, because in this project i need to use video trough PD too... so i really need to use PD and not the Arduino language...

anyway, thanks and best

Enrico

It's not difficult to sequence those messages, it is what you do with them that may pose some issues. Here's a patch, sequences are usually best done with tables or lists, but this will give you the idea.

http://www.pdpatchrepo.info/hurleur/seq_kinolab.pd

thanks a lot....

I'll trying this next week... and I'll post news soon....

best

Enrico